/*!
 * Crypto-JS v1.1.0
 * http://code.google.com/p/crypto-js/
 * Copyright (c) 2009, Jeff Mott. All rights reserved.
 * http://code.google.com/p/crypto-js/wiki/License
 */
(function() {

  // Shortcut
  var util = Crypto.util;

  var MARC4 = Crypto.MARC4 = {

    /**
     * Public API
     */

    encrypt: function(message, password) {

      var

        // Convert to bytes
        m = util.stringToBytes(message),

        // Generate random IV
        iv = util.randomBytes(16),

        // Generate key
        k = Crypto.PBKDF2(password, util.bytesToString(iv), 32, {
          asBytes: true
        });

      // Encrypt
      MARC4._marc4(m, k, 1536);

      // Return ciphertext
      return util.bytesToBase64(iv.concat(m));

    },

    decrypt: function(ciphertext, password) {

      var

        // Convert to bytes
        c = util.base64ToBytes(ciphertext),

        // Separate IV and message
        iv = c.splice(0, 16),

        // Generate key
        k = Crypto.PBKDF2(password, util.bytesToString(iv), 32, {
          asBytes: true
        });

      // Decrypt
      MARC4._marc4(c, k, 1536);

      // Return plaintext
      return util.bytesToString(c);

    },


    /**
     * Internal methods
     */

    // The core
    _marc4: function(m, k, drop) {

      // State variables
      var i, j, s, temp;

      // Key setup
      for (i = 0, s = []; i < 256; i++) s[i] = i;
      for (i = 0, j = 0; i < 256; i++) {

        j = (j + s[i] + k[i % k.length]) % 256;

        // Swap
        temp = s[i];
        s[i] = s[j];
        s[j] = temp;

      }

      // Clear counters
      i = j = 0;

      // Encryption
      for (var k = 0 - drop; k < m.length; k++) {

        i = (i + 1) % 256;
        j = (j + s[i]) % 256;

        // Swap
        temp = s[i];
        s[i] = s[j];
        s[j] = temp;

        // Stop here if we're still dropping keystream
        if (k < 0) continue;

        // Encrypt
        m[k] ^= s[(s[i] + s[j]) % 256];

      }

    }

  };

})();
